RESUMEN
BACKGROUND: There is a well-established, although complex, association between aggression and psychosis, particularly in the early stages of illness. Some persons display aggressive behaviors even prior to psychosis onset. However, factors associated with aggressive behaviors prior to and at first-episode psychosis (FEP) onset remain underdocumented. AIMS: The objective is two-fold: 1) to describe the prevalence of verbal and physical aggression occurring during the premorbid phase and at FEP onset; 2) distinguish the factors associated with aggressive behaviors during these two periods. METHOD: Data on aggressive behaviors and factors potentially associated therewith were collected through research interviews and chart reviews among 567 persons with FEP admitted to two early intervention services in Montreal, Canada. Logistic regression analyses were conducted to identify factors associated with aggressive behaviors in both periods. RESULTS: In the premorbid phase, 46.1 % (n = 257/558) of patients presented aggression (verbal: 35.9 %; towards objects: 24.2 %; against others: 27.9 %). At FEP, 18.1 % (n = 101/558) presented aggressive behaviors (verbal: 12.9 %; towards objects: 6.1 %; against others: 8.8 %). In the premorbid phase, lower education, prior justice involvement, cluster B personality traits/disorder and poorer functioning were associated with aggressive behaviors, while, at FEP, only prior homelessness was associated with aggression. CONCLUSIONS: Aggressive behaviors are frequent in patients with FEP, prior onset and at FEP. Premorbid aggressive behaviors seem to be associated with premorbid difficulties. Early detection of youth with psychosis and those at high risk of psychosis, particularly homeless youth, is necessary to provide access to early specialized interventions and possibly prevent aggressive behaviors and their consequences.